Statins and diabetes

Statins slow the action of an enzyme in the liver that plays a key role in the manufacture of cholesterol. This causes the level of blood cholesterol to drop. Find out how effective are statins for people with diabetes.

The treatment of diabetes has traditionally focused on controlling the blood sugar level through diet combined with injections of insulin or tablets.

There's no doubt that good glucose control is central to minimising the risk of long-term complications, such as damage to nerves, circulation, kidneys and eyes.

But over recent years, attention has focussed on the fact that people with diabetes are up to four times more likely to suffer a major event involving the circulation – for example a heart attack, a stroke (cerebrovascular accident) or peripheral vascular disease (reduced blood flow in the blood vessels of the legs).

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In fact, coronary heart disease is the leading cause of death in people who have both type 1 and type 2 diabetes.

All this means it's now recognised that diabetes, particularly type 2, is as much a disease of the circulatory system as it is of blood glucose control.

How can I reduce my risk?

Term watch

Cardiovascular means the heart and circulation.

Cardiovascular diseases are those diseases caused by hardening of the arteries.

Collaborative atorvastatin diabetes study (CARDS)

It looked at the benefits of taking a 10mg dose of atorvastatin daily.

None of the participants had heart disease at the start of the trial, but they did have an extra risk factor for developing it, such as smoking, high blood pressure, diabetic retinopathy (eye problems) or protein in the urine indicating diabetic kidney disease.

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For those taking the statin, the risk of heart attack reduced by 37 per cent and stroke by 48 per cent.

These benefits were seen regardless of age, sex or whether the cholesterol level was high or low.

The trial's success meant it was halted two years early.

The heart protection study (HPS)

The HPS study involved nearly 6000 people with diabetes aged 40 to 80.

It looked at the benefits of taking a 40mg dose of simvastatin each day. Just under half of the participants showed signs of cardiovascular disease, while half did not.

It found this routine use of statins cut the number of heart attacks and strokes in both groups by a third.

Cholesterol levels

Ideal level: less than 4mmol/l.

Benefits were also seen in people whose cholesterol levels were not high in the first place (less than 5mmol/l) and in those at the top of the age range.

The results showed statins can prevent cardiovascular disease, because they reduced heart attacks and stroke in people who didn't have cardiovascular disease at the start of the trial.

What are the side-effects?

Statins are generally well tolerated.

But in some people they cause headaches, affect liver function and cause stomach problems such as abdominal pain, constipation, flatulence, diarrhoea and vomiting.

Some people do get muscle aches with statins, which may settle down after a short peiord of time.

More rarely, they can cause rashes and disorder of the muscles (myopathy).

Where a statin cannot be tolerated, alternative medications such as ezetimibe or a fibrate medicine may be tried, but these medications do not lower cholesterol to the same degree as a statin, and unlike statins, do not have evidence for reducing cardiovascular disease.

Should everyone with diabetes take a statin?

According to latest NICE guidelines (2014), statins should be considered for all people with type 2 diabetes and a cardiovascular risk factors of 10 per cent or more over 10 years.

You can calculate your risk of cardiovascular disease by using the risk calculator.

Statins may be prescribed in people with type 1 diabetes if they have had diabetes for longer than 10 years or are older than 40, if there are additional cardiovascular risk factors, or if there is kidney disease (nephropathy) present.

The CARDS and HPS studies have clearly shown that statins reduce cardiovascular risk, regardless of how low cholesterol levels are in the first place.

This suggests there shouldn't be a level of blood cholesterol below which statin treatment is considered unbeneficial.

More research is now in progress to try and clarify the broader use of statins in diabetes treatment.

Below are some factors that need to be considered.

Not everyone with diabetes has the same risk: there are people with type 2 diabetes who aren't overweight. Not all smoke or have high blood pressure. So while the studies show statins are effective across the board, we can't yet say everyone should take them.

A statin is just one part of treatment: while statins reduce cholesterol levels, there are other factors that increase cardiovascular risk. This means sensible eating, exercise, good blood pressure control and avoidance of smoking and excess drinking.

In the long term

Tackling the cardiovascular risk of diabetes is every bit as important as regulating your blood sugar level.

For many people it is more important, and statins are now among the most powerful tools we have to influence this risk.

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